NCX10S SERIES
Isolated 10W Single Output DC/DC Converters
APPLICATION NOTES
benefit for a given size, cost, and power loss.
In applications where large transient load
PROTECTION
swings are expected, for example 10-60% or
25-75%, the fitting of an external electrolytic
output capacitor is recommended to reduce
voltage over/under shoot. 200µF capacitance
will typically reduce a peak excursion to
350mV settling to within 1% VNOM in 1.2ms.
Additional externally fitted capacitance will
further reduce over/under shoot.
The “absolute maximum” ratings in the
specification define conditions which may
degrade life but will not result in immediate
damage. This section of the application notes
deals with those unavoidable or accidental
occasions when the ratings are exceeded.
Radiated noise is present in magnetic and
electrostatic forms. Thanks to the small size of
these units, neither form of noise will be
radiated “efficiently”, so will not normally
cause a problem. Any question of this kind
usually better repays attention to conducted
signals.
The unit will protect itself against a wide
range of abnormal conditions. In others,
where failure is inevitable, the consequent
hazards have been minimised.
If the supply polarity is reversed, the unit is
unable to protect itself. The simple
preventative measure of a series diode would
add unacceptable power loss for the basic
product, but it may be appropriate in some
applications to fit this diode externally.
Optional Open
Collector Transistor
DC
DC
SD
SD
With no polarity protection, tracks and
components will safely fail to high
impedance, disconnecting the power. A large
fault current will occur in this process.
Less than
0.8V for
Shutdown
DC
DC
–VIN
–VIN
FUSING
1
Part Number
NCX10S24XX
NCX10S48XX
Recommended Fuses
1.6A
1.0A
Figure 6: Shutdown with Isolating Diode
100µH
100µH
10µH
DC
10µH
2.2µF
1mH
2.2µF
DC
10µF, 250Vac Y Rated
10µF, 250Vac Y Rated
Figure 7: Recommended Configuration to Reduce Noise
1 Anti surge T-type fuses are recommended
CANDD [ C&D TECHNOLOGIES ]
